Plaster-board.



' Memes:

M. K. ARMSTRONG.

PLASTER BOARD.

APPLICATION FILED JAN.4.1918.

Patented Sept. 17, 1918.v

TED STATES PATENT OFFICE.

MORGAN K. ARMSTRONG, 0F WINNETKA, ILLINOIS, ASSIGNOR TO BESTWALL MANU- FACTUR IING COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION-OF DELAWARE.

PLASTER-BOARD.

To all whom it may concern Be it known that I, MORGAN 'K. ARM- STRONG, a citizen of the United States, and a resident of Winnetka, in the county 'of Cook and State of Illinois, have invented certain new and useful Improvements in Plaster-Board; and I do hereby-declare that the following is a full, clear, and exact depointed out in the appended claims.

The object of the invention is to provide a plasterboard in which the paper is thoroughly adhered or attached to the plastic body and at the same time presents an outer,

sized surface so that theboard may be handled easily andrwithout damage or waste during the nal steps of setting the plaster and drying ,he board, and also so that .the

finished board, when used, requires no coat of sizingas in the case of a 'plaster wall to prepare its exposed surface for decoration purposes.

The advantages of my improved plaster board will be made apparent as I proceed 1 with my specification.

In the drawings:

Figure. 1. represents in perspective, a frag-' ventioil.

Fig. 2 represents on an enlarged scale, a section through said plaster board.

Plaster board is made in 'a continuous length upon a cylinder machine wherein a continuous sheet of paper is fed u'on a conveyer belt or table toward a pair 0 horizontally disposed, vertically 'spaced rolls, the distance separatin the rolls being-equal to the intended thic ess of the plaster board. As the paper sheet advances toward these rolls, a wet plastic mixture is dumped upon and spread over this sheet of paper, said sheet being the bottom covering for ment of plaster board embodying my inthe finished board. A second or top sheet of paper is fed about the top roll and is {brought into engagemen it h P face of the wet plastic material alread on the bottom sheet, and the two strips 0 paper with the plastic materialbetween them are .passed between the aforesaidmolls, thus Specification of Letters Patent.

Patented se tic, 1918.

Application flled Jaiiuaryv 4, 19i8. Serial No. 216,290.

forming the board. The continuous length of board is fed from the rolls over a long table, and during its passage over this the plaster, sets. At the end of the table it is cut into certain lengths and is placed u-pon'edge upon trucks, which are removed to a drying room for the purpose of drying out the moisture.

I have found that in the manufacture of plaster board, as thus briefly described, if the paper covering sheets are not sized, they will adhere securely to the plastic body material of the board. However, such unsized paper absorbs such quantities of moisture from the Wet plastic material as to become substantially saturated. The board, as it comes from the machine, is in a limp, soggy condition, which makes it almost impossible to subject it to thehandling required in the final drying steps of the process. On the other hand, a paper which has been thoroughly treated throughout with a suitable sizing solution, is objectionable. While the saturation of the unsized paper is eliminated andlthe board, after setting, is for that reason in better condition for handling, the

, sized paper has the defect that it does not and cannot be made to adhere to the plastic body of the board, and when said body is thoroughly dried, separation of the paper from the plastic body occurs and bulges or large blisters appear in the covering. In my improved board, the objectionable features of both sized and of unsized paper are eliminated. Y

The improved plaster board comprises top and bottom covering sheets 5 and 6,

of paper, and an intermediate body or layer .the process is called in the trade, to neutralize any sizing which may exist in the stock from which these plies are made.

. By using paper which has the outer plies sized and the inner plies unsized, I obtain a covering for a plaster board, which has not only the adhesive capacity of an unsized paper, but the stifi'enin and strength and other desirable qualities of a sized paper. v

A plaster board having top and bottom coverm of the kind above described, can

be readily handled immediately as it'comes from the table without damage, can be placed on edge on trucks and can be put in racks or hangers to be dried Without damage or slack sized. From the foregoing description, however, it will be understood that the covering sheets may either or both be of any number of plies, dependent upon the weight of pa er required to make the board to meet\ the ema-nds of any particular situation,it being only necessary in carrying out the invention, that the ply or plies. providlng .the exposed surfaces of the board, be

I As the sizing is limited to the outer plies sized, and thatthe ply or plies next adja-' after the board has'been thoroughly dried out and made ready for the market.

"- -=I claim as my invention:

1 1. A board comprising a body made of plastic materialand top and bottomcovering sheets of paper, said top and bottom covering sheets each consisting of a plurality of plies, the plies of said paper covering nearest to'the plastic body being sized and adapted to adhere to the ad aCent surface of said plasticbody, and the outer plies of said paper covering being sized.

2. A board comprising a plastic body and top and bottomcovering sheets of paper, each covering sheet consisting of a plurality of plies, the plies of said covering sheet near said plastlc body being slack sized and adapted to adhere permanently to said plastic body, and the plies remote from said plastic body and providing the outer surface of the board, being thoroughly sized. In testimony that I claim the foregoing as my invention, I afiiX my signature in the presence of two witnesses, this 19th day of December, A. D. 1917.

MORGAN K. ARMSTRONG. Witnesses:

T. H .ALFREDs, D. DARBENOUGUE. 

